Optimal power allocation scheme on generalized layered space-time coding systems

We consider a generalized layered space-time (GLST) architecture with parallel space-time (ST) codes and derive an optimal power allocation (PA) scheme over the space-time encoders to minimize the overall frame error rate. We prove that the optimal power allocation scheme will equate the derivatives of the frame error rate functions of all the ST codes. From simulation, we show that the derived optimal power allocation has a 1-2 dB gain over the equal power scheme. Also, the proposed scheme has a better performance than the power allocation scheme proposed by Tarokh, Naguib, Seshadri and Calderbank (see IEEE Trans. Inform. Theory, vol.45, no.4, p.1121-28, 1999). Since various power allocation schemes have the same receiver structure, the gain can be achieved simply using the optimized parameters with no increase in complexity.